The long term objectives of this proposal are to study two well defined African populations from Nigeria to determine the contribution of 14 polymorphic genes involved in lipid metabolism in determining quantitative lipoprotein-lipid and apolipoprotein levels as these are major risk factors for coronary hear disease, and to investigate how differences in life styles and dietary habits modulate the genetic contribution on these quantitative risk factors. Phenotypes in the gene products of APOs A-IV, C-II, D, H, J and (a) will be determined by IEF and SDS/immunoblotting and genotypes at the B,E, AI-CIII- AIV cluster, lipoprotein lipase, hepatic lipase, LDL-receptor, and cholesterol ester transfer protein will be determined by polymerase chain reaction protocols. The quantitative levels of total cholesterol, HDL-cholesterol and its subfractions, HDL2- and HDL3-cholesterol, triglycerides and LP(a) will be used in the genetic analyses. Estimates of the effect of alleles at each of the candidate loci on quantitative lipoprotein-lipid levels will employ the measured genotype approach. The effect of multisite haplotypes for RFLP at various loci, where applicable, will also be estimated using the same method. The interaction of alleles at various independent loci in determine quantitative lipoprotein-lipid and apolipoprotein levels will be estimated. In addition to the measurements of environmental effects, we will also measure the genotype-environmental interaction in determining quantitative risk factor traits.